Hi, I failed to take the call control using 3CX windows softphone with Sennheiser SC60 headset. Already downloaded and installed the Sennheiser 3CX phone plugin and upgrade the firmware of SC60 to the latest version. My 3CX windows phone version is 15.5.3849.1. Following the steps at https://www.3cx.com/docs/configuring-sennheiser-headsets/. Just volume control works. But answer and reject a call do not work. Can anyone help?